Lung Nodule Detection Using PET/MRI

Techniques for lung nodule examination are strongly dependent on the size of the suspected lesion. In patients without risk factors for malignancy, lung nodules of ≤6 mm are regarded as unspecific. CT examinations are usually performed in pulmonary nodules ≤5 mm surrounded by lung parenchyma, since PET and MRI examinations are more reasonable in lesions of ≥7 mm. CT findings describing benign lesions are calcifications within the lesion, density values ≤10 HU, and the absence of changes in size over 2 years. As stated by the Fleischner Society, the need for further investigations of lung nodules is dependent on nodule diameter and on patients’ risk factors. The presence of risk factors might result in additional contrast-enhanced CT examinations, PET examinations, or biopsies. In this chapter we explore the use of PET/CT in this clinical indication and introduce the possible use of PET/MRI in future directions.